The game won't properly load worlds that have period (.) on folder name - they'll be loaded as glitched worlds that don't have world name and last played date set as 1970-01-01. Trying to open any of them will generate new world with world folder name being cut (for example, if folder name was Test.Hello, a new world will generate with name Test).

How to reproduce:

1. Rename world folder name to something that contains period (.)
2. Open the game
3. Press play button
4. See that world won't load properly